1. Field of the Invention
This invention concerns detergent compositions. More particularly, this invention concerns highly alkaline detergent compositions. Even more particularly, the present invention concerns pellets of highly alkaline detergents and processes therefor.
2. Prior Art
The use of highly alkaline detergent compositions for warewashing is widely known. There is a wealth of prior art which teaches alkaline powders, flakes, emulsions, liquids and the like.
Likewise, the art has taught that the incorporation of adjuvants, such as, surfactants, chlorine-sources, chelants, sequestrants and the like is highly desirable in alkaline detergents and especially, in highly alkaline detergents. Furthermore, the art has recognized that the inclusion of complex metal phosphates in highly alkaline detergents is desirable in not only enhancing detergency but, also, because of their sequestering capabilities in hard water environments. However, the art has further recognized the inherent problems of phosphate reversion and the degradation of active-chlorine sources in highly alkaline environments and has sought suitable solutions therefor.
With respect to the phosphate problem, the art has directed its attention to either finding suitable alternative replacements for phosphates, such as alkali metal gluconates, nitrilotriacetates and the like, or to reducing the amount of reversion of the complex phosphate in such alkaline systems.
The use of alternates has not met with much market success. Recently, though, the art has seen the advent of solid, cast, brick-type, highly alkaline detergents, which contain both alkaline materials and complex phosphates. While such detergents have a high percentage of active phosphate when first formulated, they quickly lose active-phosphate content because of the reversion encountered during processing due to high processing temperatures and the like. In spite of this, these cast solid detergents have enjoyed wide commercial success because of their ease of handling and the like. These highly alkaline cast detergents are more particularly described in Fernholz et al, U.S. Pat. Nos. 4,569,780 and 4,569,781, the disclosures of which are hereby incorporated by reference.
Regarding the problem of chlorine degradation, the art has paid little attention thereto, other than proposing the use of plugs of active-chlorine employed within solid, cast detergent bricks.
However, and as noted above, the art still requires means and methods for decreasing phosphate reversion and reducing the amount of chlorine degradation in highly alkaline detergent products. It is to this to which the present invention is directed.